ARETE (O. Fr. areste, Lat. arista, ear of corn, fish-bone or spine), a ridge or sharp edge; a French term used in Switzerland to denote the sharp bayonet-like edge of a mountain (such as the Matterhorn), that slopes steeply upward with two precipitous sides meeting in a long ascending ridge. Hence the word has passed into common use to denote any sharp mountain edge denuded by frost action above the snowline, where the consequent angular ridges give the characteristic "house-roof structure" of these altitudes.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)